The present invention relates to a new and improved apparatus for detecting flaws or defect locations at the surface of a moved reflecting material.
The apparatus of this development is of the type embodying a light source and a first optical system which directs the light thereof successively upon a surface region of the material located along a line extending essentially transversely with respect to the direction of movement of the material. There is also provided a photoelectric transducer and a second optical system which collects the light reflected from the individual surface regions at the transducer, and an indicator device which as a function of the intensity of the light reflected by each surface region generates a signal, especially an optical signal, which is associated with the relevant surface region. Equipment of this type is particularly employed for the surface control during the fabrication of photographic materials, such as films, paper, etc.
With known apparatuses of this type there is illuminated, through the agency of a movable optical system, in succession partial zones or regions of the material web to be examined (flying-spot-technique), and imaged via a second optical system at a stationary light detector. These prior art apparatuses are relatively complicated and require large optical components which extend over the entire width of the material web and past the same. Since such large optical components are difficult to fabricate and thus expensive the state-of-the-art apparatuses are only suitable for relatively small material web widths.